A distributed communications system comprises a plurality of interconnected communications devices (e.g. call processing devices such as telecommunications installations or else data processing devices). Such a distributed communications system normally has one or more connections to public communications networks. Connection requests relating to a called subscriber within the distributed communications system are switched to the called subsriber's associated communications device on the basis of the dialed destination call number of the called subscriber. This communications device sets up a connection to a terminal associated with the called subscriber. The subscriber is associated with his terminal generally by a destination call number associated with the respective called subscriber.
In modern communications systems, a subscriber is frequently not associated with a terminal by a fixed destination call number, however. Instead, a subscriber logs onto a largely arbitrary communications terminal, e.g. by entering a code number, in order to have connection requests intended for him put through.
This method is found to be particularly advantageous for telephone service centers in which a shared collective call number can be used to reach a group of telephone operatives. In such a case, the selection criterion according to which an incoming call is put through would be the availability of a respective operative in this group, for example.
A mark of today's telecommunications is a convergence of telephony and data processing functions. The organization ECMA (European Computer Manufacturer Association) is therefore working on standards which make it possible to support telephony functions on a data processing workstation. The ECMA standard ECMA-269, 4th edition, June 2000: “Services for Computer Supported Telecommunications Applications (CSTA) Phase III” discloses, by way of example, a method for automatic call distribution, known in the technical field by the abbreviation ACD. In this context, for “ACD Devices Categories”, that is to say physical (devices) or logical (software applications) telecommunications units, characteristic properties are defined which are described in section 6.1.3.4.3 “ACD Device Categories” of said standard. Activities taking place between these telecommunications units are managed by “agents” (cf. section 6.1.3.7, “Agent”) using software, an agent representing a telecommunications unit onto which a subscriber has been logged by a logon process.
Telecommunications functions are incorporated within data processing installations by programming interfaces. The best known programming interfaces of this type are TSAPI (Telephony Service Application Programming Interface), TAPI (Telephony Application Programming Interface) and the CSTA standard (“Computer Supported Telecommunication Applications”).
On the basis of the CSTA standard, in the case described above for a telephone service center, subscribers whose terminals are associated with a group are represented by an agent when a logon process has been performed using a registration function. Using this agent, a connection request arriving is distributed according to prescribable criteria, irrespective of the destination call number of the respective terminal. The registration function is in the form of software which is executed during the logon process, e.g. by entry of a code number by the subscriber who is logging on. This identifier is used to associate the subscriber logging on with a group.
The German patent application carrying the file reference 10102174.7 has proposed a method in which a plurality of communications devices in the same communications system are involved in call distribution, a group being able to comprise a plurality of communications devices within the communications system.
In many communications systems, the need arises for an automated call answering function to be provided. In the case of the aforementioned telephone service centers, this automated call answering has, by way of example, the function of informing a calling subscriber that he has been put in a queue and will be connected to the next available operative. On the other hand, automatic call answering can also have the function of informing the calling subscriber about the location of a called subscriber who is not available, and possibly of providing the calling subscriber with the opportunity to record a voice message.
Automated call answering can be managed and set by a subscriber on his terminal. The communications device to which the terminal of this subscriber is connected thus manages the—possibly subscriber-specific—voice message when this subscriber cannot be reached, and stores voice messages left for him. If a communications system contains a network of installations which comprises a plurality of communications devices, then the problem arises that, although a subscriber can log onto an arbitrary terminal on the basis of the German patent application specification's method described above, in which case he is not tied to a communications device associated with him, he is tied to his associated communications device for the purpose of managing his subscriber-specific, automated call answering.